Re: Caps for Short Term Mobil Energy Storage
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Posted by Dan Coby on August 13, 2008, 7:43 pm
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>> According to the data given, 1 square meter of water pumped up to a height
>> of 30 meters weighs 1000 kg, and has a potential energy of 30 kJoules. This >> is enough energy to power a 30 watt lamp for 3.3 hours. >
> Er.... I make that 1000 seconds, which is more like 17 minutes, not > three hours. > Not 3.3 hours, either. > > also, don't you need to know how much mass of water (i.e. not square > meters, > but cubic meters?) Or, is this a 1 square meter column of water 30 > meters high? Actually the potential energy is given by m*g*h. Where m is the mass, g is the gravitational constant (9.8 m/s/s at the earth's surface) and h is the height. Assuming 1 cubic meter, then you get 294 kJ or 9800 seconds for a 30 watt lamp (2.72 hours). | ||||||||||
